“Humility,” Bush responded Thursday when asked about the most important trait for a president to have, NPR reports. “I think it’s really important to know what you don’t know and listen to people who do know what you don’t know.”

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“Realize it’s about the people, not you,” Clinton elaborated. “A lot of these people who are real arrogant in office, they forget. … You don’t want to say, ‘God, look at all those people I beat.'”

The two men, who are good friends and like to say that they’re each other’s “brother from a different mother,” as Bush quipped Thursday, also joked around during the conversation. When Clinton said the best thing for a politician is to be “consistently underestimated,” Bush replied, “I was pretty good at that.”